A safety shoe having a hard toe cap embedded at a toe section has been known. Use of safety shoes increased since around 1955 (i.e., around the year Showa 30) to prevent accidents to foot. In 1972 (i.e., Showa 47), it became compulsory by Article 558 of Ordinance on Industrial Safety and Hygiene to wear safety shoe, and the standard thereof was established at the same time (see Non-patent document 1). Further, in many countries of the world, similar standards were established (see Non-patent document and the like).
A toe cap is embedded at a toe section of a shoe to protect toe, which is the most important element of a safety shoe and a protective sneaker, and performance and strength of the toe cap are defined in detail in the above standards. However, there has been a problem that a digitus quintus (i.e., a little toe) cannot be protected due to a reason in association with bending of the shoe. Accordingly, accidents damaging little toes caused by a dolly and the like which runs over a little toe laterally were not negligible among foot accidents.
The material of a toe cap varies from steel to resin, while the shape is formed to have a cup-shaped (alternatively, described as arch-shaped or dome-shaped) shell body which mainly covers a toe region from the base of a thumb, a skirt formed at a bottom face by folding the outer circumferential end inwardly, and an opening formed at a rear side to provide a foot inlet portion, as illustrated in drawings of Patent documents 1, 2 and 3.